Telephone-exchange system.



H. P. CLAUSEN.

'IELEPHONE EXCHANGE SYSTEM. APPLICATION FILED OCT. 12. 1915.

1,257,317. Patented Feb. 26,1918;

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Henry F C/musen y 'Afiy.

UNITED gTATES PATENT HENRY P. CLAUSEN, 0F MOUNT VERNON, NEW YORK, ASSIGNOR, BY MESNE ASSIGN- If. ENTS, TO WESTERN ELECTRIC COMPANY, INCORPORATED, A CORPORATION OF NEW YORK.

Application filed October 12, 1915.

T 0 all whom it may concern:

Be it known that I, HENRY P. CLAUSEN, a citizen of the United States, residing at Mount Vernon, in the county of lVestchester and State of New York, have invented certain new and useful Improvements in Telephone-Exchange Systems, ofwhich the following is a full, clear, concise, and exact description.

This invention relates to telephone exchange systems, and more particularly to improvements in telephone trunk circuits.

The object of this invention is to provide means for rendering more efficient service in the handling of connections over trunk circuits in which the transactions may require that the originating operator be signaled by the operator at the call-receiving end of the trunk circuit to come in on the connection. Transactions of this nature are frequently handled between the operators positions of a telephone switchboard and an information operators desk; therefore, for convenience, this invention will be disclosed in a manner suitable for rendering this service.

In accordance with this invention, a trunk circuit having a call-originating end and a call-receiving end is equipped with relays, a signal at the call-receiving end, a source of tone-signaling current, and circuit interrupting means. After a connection has been completed over the trunk circuit, a supervisory signal in the link circuit, used at the originating end, may be caused to render a continuous automatic flashing indication in response to a momentary disconnection of the link circuit used at the receiving end. In turn, a momentary disconnection of the circuits of the link circuit at the originating end results, first, in a discontinuance of the flashing operations, second, to momentarily operate a supervisory signal in the link circuit used at the receiving end, and third, to momentarily include the source of tone-signaling current with the operators telephone set at the receiving end of the trunk circuit.

Briefly described, the features of particular advantage, present with this system, in

the l ed e eb ree h esa e a ja .0a T Tear n am .2 sad Specification of Letters Patent.

TELEPHONE-EXCHANGE SYSTEM.

Patented Feb. 26, 1918.

Serial No. 55,400.

switchboard positions of a telephone exchange and an information operators desk, are as follows: In signaling from the information desk for a switchboard operator to come in on a previously completed trunk connection, the information operator is, after a first momentary manual operation, relieved from further action until notified by the tone signal. On receiving the tone signal, the information operator imme diately proceeds to instruct the switchboard operator relative to the further handling of the call, and without an oral challenge, as the tone indication signifies that the switchboard operator is waiting on the connection. The automatic flashing of the supervisory signal at the switchboard is a particularly conspicuous indication, and results in reducing the time required in attracting the attention of the switchboard operator.

In the drawing is illustrated diagrammatically at A and B such portions of wellknown central-energy telephone link circuits as will be necessary in describing the features of this invention. At C is similarly illustrated a trunk circuit completely equipped in accordance with this invention.

In describing the operation of this system, let it be assumed that the link circuit A forms a part of the regular equipment at a telephone switchboard position, while the link circuit B, adapted to be included with the telephone set 18, is located at an information operators desk.

Referring to the drawing, the insertion of a plug 5 in a jack 6 completes a circuit through the ring contacts 7 and 8 of the plug 5 and the jack 6, respectively. The circuit thus completed includes a relay 11 and a relay'12 in series with a battery 1. circuit completed through the tip contacts 9 and 10 of the same plug and jack, respectively, includes a relay 14 and a relay 15 also in series with the battery 1. A trunk signal lamp 18 at the information desk B is now lighted through a circuit from the .battery 1, contacts 27 of a relay26, and the contacts 16 of the relay 15, to earth. In response to this signal, a plug 19 is inserted in Another;

22 of this plug and jack, respectively, completes a series circuit through a relay 25, the relay 26, and the battery 1. The tip contacts 23 and 2% of the same plug and jack, respectively, completes another series circuit, which includes a relay 30, a relay 31, and the battery 1. The signal lamp 18 is now disconnected by the separation of the contacts 27 of the relay 26, and the contacts 28 of this relay now complete the circuit of a main conductor of the trunk line C. The energization of the relay 31 does not immediately result in current action, but circuits are prepared for subsequent steps in the handling of this connection, as will presently appear.

A connection is now completed over the trunk circuit C, and the information operator at B may talk directly with a subscriber whose line may be assumed to be connected with the answering end (not shown) oi the link circuit A.

Let it now be assumed that the information operator at B desires to instruct the switchboard operator at A relative to "further handling of the call for the connected subscriber. The plug 19 is withdrawn from the jack 20 a sufficient distance to separate the respective contacts of the plug from those of the jack, after which the plug is immediately reinserted in the jack. The relay 31 is provided with a copper secondary in order to retard its release suiiiciently to insure that the relay 26 will have re leased first, all in response to the momentary removal of the plug 19 from the jack 20. The contacts 27 of the relay 26 close a circuit which includes the battery 1, the winding of the relay 35, its contacts 36, contacts of the relay 31, contacts 27 of the relay 26, and the contacts 16 of the relay 15, to earth. Over this circuit, relay 35 receives an initial operating impulse of current, after which its complete operation is effected over its own contacts 37, which closes circuit in advance of the separation of its contacts 36. Thereafter, the relay 35 is locked through its contacts 37 independently of the contacts 32 of the relay 31 and the contacts 27 of the relay 26, through which circuit the relay 35 received the initial impulse of operating current. A. branch circuit is now completed from the main conductor 40 of the trunk circuit C by means of -a conductor 41, the contacts 33 of the relay 31, the contacts 38 of the relay 35, and a circuit interrupter wheel 2, to earth. Through this derived circuit, the potential of the trunk conductor 40 is alternately reduced from the potential normally present during a connection at the tern'iinals oi the relay 1% to zero, corresponding with the earth connection. These changes of potential occur in synchronism with the opening and closing or" the circuit through the in;

terrupter wheel A supervisory relay 1% in responding to these changes in current action on the conductor 40, renders flashing indications on the supervisory lamp 13, the circuit of the lamp 13 being further completed through the contacts of the relay 11, which is energized as already described. In answer to the flashing signal, the operator withdraws the plug 5 from the jack 6 either entirely or only suiiiciently to separate the contacts of the plug from the respective contacts of the jack, the plug 5 being immediately reinserted in the jack 6. This mo-- inentary disconnection of the link circuit "from the trunk conductors permits the re lease of the relay 15, and the separation of its contacts 16 disconnects t 1e relay 35. The relay 35, as indicated in the drawing, is adapted to release slowly. Therefore, dur ing the retarded releasing period of this relay, a circuit is momentariiy closed from the battery 1, a tone-signaling current interrupter 3, the contacts 17 of the relay 15, conductor l2, contacts of the relay 35, and the information opcrators telephone set 43, to earth. At the same instant a fur ther circuit action is present, due to the momentary releasing of the relay 12, its contacts close a branch circuit from the main conductor e5 01": the trunk circuit by way of the contacts 23 of the relay to earth. This derived circuit reduces the current po tential across the terminals of the supervisory relay 30 to zero. The resulting 1110- mentary release of the relay 30 causes a supervisory lamp 29 to be lighted, the further circuit of this lamp being completed through the contacts of the relay 25 already operated. The relay 35 having finally released, disconnects, by the separation of its contacts 38, the circuit interrupting wheel 2, thereby discontinuing the flashing operations on the supervisory lamp 13 at A. At the instant the plug 5 was removed from the jack 6, the operator at A also placed a listening key (not shown) of the link circuit in the talking position. On receiving the tone signal, the information operator thereby understands that the switchboard operator is waiting on the trunk connection. it, for any reason, the information opera tor should delay in responding to an answering switchboard operator, the switchboard operator may, by alternately removing and reinserting the plug in the jack 6, cause the supervisory lamp at the information desk to be flashed. as already described. This subsequent flashing of the supervisory lamp 29 does not, however, include the tonesignaling current with the information opcrators set, as the circuit of the tonesignaling current is disconnected by the separation of the contacts 39 01 the relay 35.

Ordinarily, information service requires that the switchboard operator will be the first to remove a connection from the trunk circuits. Therefore, when the plug 5 is withdrawn from the jack 6 at A while the plug 19 remains in the jack 20 at B, the supervisory lamp 29 will be lighted over the circuits al ea dy described in connection with the flashing operation for this lamp. In

case the plug 19 is removed from the jack 20 during the time the plug 5 is in the jack 6, the lamp 18 of the trunk circuit will be lighted.

A condenser shown in each of the main conductors of the trunk circuit C serves to separate the battery current paths at opposite ends of the trunk circuit.

It will be understood that a suitable switching means may be employed either in the link circuits or in the trunk circuit for the purpose of momentarily opening the circuits as described for initiating and restoring the automatic flashing signals, instead of opening the trunk circuit by the momentary removal of the plugs. Although sevoral batteries have, for convenience, been shown in the drawing, it will be understood that these batteries may be and preferably are one and the same battery.

What is claimed is:

1. A telephone exchange system comprising a trunk circuit extending from a first to a second switchboard, a link circuit at each switchboard connected with the trunk circnit, a signaling device at the first switchboard, interrupter mechanism, operator controlled switching mechanism at the second switchboard, and a relay operating upon the momentary actuation of the operator controlled switching mechanism for including the interrupter mechanism and the signaling device in circuit relation thereby causing the intermittent operation of the signaling device.

2. A telephone exchange system comprising a trunk circuit extending from a first to a second switchboard, a link circuit at each switchboard connected with the trunk circuit, a signaling device for the link circuit at the first s *itchboard, interrupter mechanism, a switching relay operating upon the momentary disconnection of the link circuit at the second switchboard from the trunk circuit to establish circuit relation between the interrupter mechanism and the signaling device thereby to cause the intermittent operation thereof, and an operator controlled switching device at the first switchboard for discontinuing the intermittent operation of the signaling device.

3. A telephone exchange system comprising a trunk circuit extending from a first to a. second switchboard, a link circuit at each switchboard connected with the trunk circuit, an operators telephone set at the second switchboard, a source of tone signaling current, and switching means at the first switchboard controlling the inclusion of the tone signaling current in circuit with the operators telephone set.

4. A telephone exchange system comprising a trunk circuit extending from a first to asecond switchboard, a link circuit at each switchboard connected with the trunk circuit, a signaling device for each link circuit, an operators telephone set at the second switchboard, interrupter mechanism, switching means at the second switchboard controlling the inclusion of the interrupter mechanism in circuit relation with the signaling device at the first switchboard thereby to intermittently operate said device, a source of tone signaling current, and switching means at the first switchboard controlling the inclusion of the tone signaling current in circuit with the operators telephone set.

5. A telephone exchange system comprising a trunk circuit extending from a first to a second switchboard, a link circuit at each switchboard connected with the trunk circuit, an operators telephone set at the second switchboard, a source of tone signaling current, a switching relay operated upon the momentary disconnection of the link circuit at the second switchboard from the trunk circuit, and a circuit for said source of tone signaling current and said operators telephone set including a contact of said switching relay established upon the momentary disconnection of the link circuit at v the first switchboard from the trunk circuit. 100

6. A telephone exchange system comprising a trunk circuit extending from a first to a second switchboard, a link circuit at each switchboard connected with the trunk circuit, a signaling device for the link cir- 105 cuit of the first switchboard, interrupter mechanism, switching means for establishing circuit relation between the interrupter mechanism and the signaling device thereby to intermittently operate said device, oper- 110 ator controlled means for discontinuing the intermittent operation of the signaling de vice, and signaling means rendered efiective thereupon to furnish a signal to the operator at the second switchboard.

'7. A telephone exchange system comprising a trunk circuit extending from a first to a second switchboard, a link circuit at each switchboard, a signaling device for the link circuit of the first switchboard. an 120 operators telephone set at the second switchboard, a signaling device in the trunk circuit and located at the second switchboard operating upon the connection of the link circuit at the first switchboard 125 with the trunk circuit. a switching device operating upon the connection of the second link circuit with the switchboard to disable the signaling device, interrupter mechanism, switching means operated by the 130 1% the signaling device at the first switchboard a source of tone signaling current, and switching means responslve to the d1sconnection of the link circuit at the first switchboard from the trunk circuit to include the source of tone signaling current 9 in circuit with the operators telephone set.

In Witness whereof, I hereunto subscribe my name this 11th day of October, A. D. 1915.

HENRY P. CLAUSEN.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. C. 

